"You may assign an interface one primary and multiple secondary addresses.

In some cases, you need to assign secondary IP addresses to the interface. For example, if the interface

connects to two subnets, to enable the device to communicate with all hosts on the LAN, you need to

assign a primary IP address and a secondary IP address to the interface."

Please note that the physical ethernet interfaces (ports) are layer 2 interfaces by default. This will not allow to configure IP addresses on the physical interface. You can set an Ethernet port as a Layer 3 Ethernet interface by using the